My group has just finished the Well of Demons, the final encounters went well. Smoothly for them, even.
Party Composition (All 6th Level)
Drow Warlock (Dark Pact)
Eladrin Wizard (Orb)
Human Cleric of Tempus (Strength-based)
Minotaur Fighter (Battlerager)
Halfling Rogue (Artful Dodger)
Blood Pool Room
The PC's had the most trouble with this room out of all of the four they went through last night. The lashing statues kept them in the blood and savaged by the Evistro who were continually getting cover by going underneath the blood. Once the PC's figured out they could break the statues and destroyed the Eastern one, however, the tempo swung fully back into their favor.
The Drow Warlock went down during this fight, and the Rogue went down for a round when she ended up flanked by two of the demons. If I were to run this encounter again, I think I would have held off on the Western Evistro's entrance into the combat until a character was riding across the blood on a Tenser's disk after the players disabled the second statue with Magic Missle and Eldritch Blast.
Pillar Room
The PC's destroyed this room with very little difficulty. The Wizard kept the two northernmost Evistro back through repetitive use of Thunderwave and orb-sustained Icy Rays while the rest of the party cut through the other demons with a barely restrained vengeance for the troubles they were given in the previous room. Once the Barlgura was marked by the Fighter, it was all over.
The rogue did end up losing her save against the Dagger from the Blood Pool room, however, and shanked one of the party members (dropping him to negatives). She was thumped unconscious and restrained until the end of the counter...thankfully for her, she only lost the save on the next to last round of the combat.
If I ran this room again, I would have used the Barlgura's climb speed more judiciously, moving him past the front line of fighters and back to the squishy second-line sooner.
Dragon Room
The PC's pulled out of all the trapped rooms in their first two rounds, only suffering from one crossbow shot, and one scare. The elemental vortex missed the rogue, and they gathered up in the skeleton room. The Cleric kept the skeletons out of the fight by continually hitting them with radiant damage, and the others walled up against the western door of that room and played "tempt fate" with the dragon.
Righteous Rage of Tempus + Fighter Daily Power + Walking Wounded = Bad Time for the skirmisher dragon. Even though the dragon managed to drop the rogue, no lasting damage was inflicted on the party.
Were I to run this one again, I would have had the dragon take a hit from the Doom Sphere to use his Luring Gaze to pull someone out into the hallway with him, and then savage them horribly.
Maldrick Scarmaker
This room was a little tricky.
The Wizard and his Master's Wand of Magic Missile's helped out a lot, pushing an Evistro into one of the bubbling cauldrons. The Fighter tanked the skeleton AND the Barlgura by hitting the skeleton with a power that kept it marked until the end of the combat, and then ignoring its melee attacks and focusing on the Demon.
The Warlock bounced back and forth between melee and range cursing targets and hoping for their death, while Maldrick kept the group away with one of his at-will's. After the first villager died, the wizard had the bright idea of getting the other villager out of the circle by pushing it with a magic missile (due to the Wand's power). Unfortunately, this killed the villager and ruined Maldrick's plan anyway.
Eventually, the fight came down to Maldrick and one Evistro against the group. And, I got to pull the move I asked about earlier on the forums. He hit the minotaur with Infernal Moon's Curse and levitated him, then the Evistro pushed him over the cauldron. That round, the PC's killed Maldrick and the minotaur fell into the bubbling pot of evil. The damage drove him to 2 HP, and the damage from the beginning of his turn put him deep into negatives.
A Healing Word saved him after they tipped the pot over, however. If I ran this one differently, I would have had Maldrick move into more of a floating melee role, despite his artillery role. With his tail strike and his powerful warlock abilities, he'd be much better in a mixed-melee with the other monsters.
Welp, hope that was helpful!